A motor is an apparatus that rotates when a current is supplied thereto. When the current is supplied to the motor, an electrical interfering signal is generated, which possibly gives an adverse effect to an operation of a drive circuit housed in the motor. Advanced downsizing of motors makes it difficult to ensure a distance between an interfering signal generation source and a drive circuit as well as a ground (GND) area on a circuit board. This remarkably increases an adverse effect on the interfering signal.
Particularly, the interfering signal that is superimposed on a Hall signal used for detecting the position of a rotor causes misrecognition of the rotor position, a rotational speed, or a rotation direction. This may hinder appropriate energization. Accordingly, when being inappropriately energized, a conventional motor possibly causes an unstable operation such as overcurrent, vibration, or noise.
To solve this problem, when the conventional motor is driven, an analog filter including, for example, capacitors and resistors is employed to remove such an interfering signal. Furthermore, when the conventional motor is driven, instead of performing recognition of an actual rotation direction, a case where an order of signals, which is determined based on a directed rotation direction, is disturbed is treated as an error (for example, refer to PTL 1).